Assembly for controlling the gas flow in a plasma spraying apparatus

Abstract

A plasma spraying assembly comprising a treatment chamber and a plasma spraying device located in the interior thereof is disclosed that further comprises an assembly for controlling the gas flow in the interior of the treatment chamber. In order to prevent a gas flow in the interior of the treatment chamber that whirls deposits to be created, a deflection device is provided that is located at least partially in the interior of the treatment chamber. Vertically below the treatment chamber, a collecting shaft is located. In the region between the treatment chamber and the collecting shaft, there is provided a basic element comprising baffle members, but leaving open a passage between the treatment chamber and the collecting shaft. In the interior of the collecting shaft, a deflection element is located having essentially conical shape and towering into the passage of the basic element. The collecting shaft is in operative connection with the suction side of a blower and with a vacuum pump.

Description

The present invention refers to an assembly for controlling the gas flow in a plasma spraying apparatus that comprises a treatment chamber and a plasma spraying device located in the interior of the treatment chamber.For plasma coating of substrates, in most cases a plasma spraying apparatus is used that comprises a treatment chamber in the interior of which an atmosphere is created that is most suitable for a particular coating operation. Thereby, a plasma jet is generated by means of a plasmatron. In that plasma jet, the coating material to be applied to the surface of a substrate is molten. The plasma jet can reach a very high velocity, up to the ultrasonic region. However, in the interior of the treatment chamber, a gas flow is created during the operation of the plasmatron, particularly caused by the plasma jet. Such a gas flow can have a negative influence on the purity of the surface of the substrate as well as on the quality of the coating applied to the surface of the subst...

AI Technical Summary

Benefits of technology

It is therefore an object of the invention to provide a plasma spraying assembly for treating the surfaces of substrates by means of which the adhesion and the quality of the coating applied to the surfaces of the substrates is substantially improved.

Problems solved by technology

However, in the interior of the treatment chamber, a gas flow is created during the operation of the plasmatron, particularly caused by the plasma jet.

Such a gas flow can have a negative influence on the purity of the surface of the substrate as well as on the quality of the coating applied to the surface of the substrate.

Thereby, these deposits can reach the surface of the substrate to be coated and contaminate it.

It is understood, one the one hand, that a contamination of the surface of a substrate has a negative effect on the adhesion of the coating to be applied, and, on the other hand, that those impurities molten in the plasma jet influence the quality of the coating applied to the surface of the substrate to the worse.

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